1. Technical Field
The present disclosure relates to driving Light-Emitting Diode (LED) lamps and, more specifically, to regulating the energy supplied to the LED lamp under multiple operating conditions.
2. Description of the Related Arts
A wide variety of electronics applications now use solid state lighting (SSL) devices, such as LED lamps, as replacements for incandescent lamps. These applications include architectural lighting, automotive lighting, backlights for liquid crystal display devices, flashlights, and electronic signs. SSL devices have several advantages compared to incandescent lamps, including higher efficiency, improved directionality, improved reliability, longer life time, and smaller size. Many of these advantages have helped drive the adoption of SSL devices for applications that traditionally use incandescent lamps.
In some applications, however, the adoption of SSL lamps as being suitable replacements compared to other lighting methods has been slow. For example, in applications where the brightness of the light source is adjusted, such as in a dimmable lighting system, methods employed to drive an incandescent lamp, if applied to an LED lamp, may cause the LED lamp to prematurely turn off when the LED lamp is in an ON phase, resulting in a perceivable flicker. Output regulation techniques may be employed to insure a constant light output from the LED to reduce flicker. These techniques, however, often cause the dimmer switch to provide maximum of light output from the LED under all operating conditions. Moreover, LED output regulation control schemes suited for dimmable lighting system may not be suitable for LED lighting systems that do not use dimmer switches.